i think the problem is you simply don't shade enough. like, there is really not much going on. what i would suggest is
- learn hue shifting. no matter what style of skin you do this will immediately help you improve.
- study skin-makers that you like (yes, this is okay. don't feel ashamed to do so. as long as you aren't just full on copying them) and try to create a style for yourself. or, you can just use a style that already exists and that multiple people already use.
until you do those two things it's kinda hard to help you because again you don't really have much shading going on, which, tbh can be a style if it's done right
